We investigate the continuous-time dynamics of highly entangling intermediate-scale quantum circuits in the presence of dissipation and decoherence. By compressing the Hilbert space to a time-dependent “corner” subspace that supports faithful representations of the density matrix, we simulate a noisy quantum Fourier transform processor with up to 21 qubits. Our method is efficient to compute with a controllable accuracy the time evolution of intermediate-scale open quantum systems with moderate entropy, while taking into account microscopic dissipative processes rather than relying on digital error models. The circuit size reached in our simulations allows to extract the scaling behavior of error propagation with the dissipation rates and the number of qubits. Moreover, we show that depending on the dissipative mechanisms at play, the choice of the input state has a strong impact on the performance of the quantum algorithm.

中文翻译：

---

嘈杂的高度纠缠量子电路的连续时间动力学和误差缩放

我们研究了在存在耗散和退相干的情况下高度纠缠的中尺度量子电路的连续时间动力学。通过将 Hilbert 空间压缩为支持密度矩阵忠实表示的时间相关“角”子空间，我们模拟了具有多达 21 个量子位的嘈杂量子傅立叶变换处理器。我们的方法可以有效地以可控精度计算具有中等熵的中尺度开放量子系统的时间演化，同时考虑微观耗散过程而不是依赖数字误差模型。在我们的模拟中达到的电路尺寸允许使用耗散率和量子比特数提取误差传播的缩放行为。此外，我们表明，根据发挥作用的耗散机制，